The research proposed in this application will determine the initial efficacy, safety and tolerability of a novel drug combination, bupropion and naltrexone, as a pharmacotherapy for cocaine dependence. A rigorous, inpatient human laboratory study will be conducted. The proposed study is innovative and important because it will provide the impetus for the conduct of double blind, placebo-controlled trials to further demonstrate the efficacy of bupropion-naltrexone combinations for managing cocaine dependence.